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(N0 Models) J. T. JAQUES. MANUFACTURE OF INSULATED ELECTRICALGONDUGTORS.

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UNITED STATES PATENT OFFICE.

JOHN T. .IAQUES, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE EARADAYELECTRIC CABLE COMPANY.

MANUFACTURE OF INSULATED ELECTRICAL CONDUCTORS.

. SPECIFICATION forming part of Letters Patent No. 369.793, datedSeptember 13, 1887.

Application filed March 14, I885. Serial No. 158,774. (No model.)

To all whom it may concern.-

Be it known that I, JOHN T. J nouns, of Boston, in the county of Suffolkand State of Massachusetts, have invented certain Improvements in theManufacture of Insulated Electrical Conductors, of which the followingis a specification.

My invention relates to the manufacture of insulated electricalconductors.

The object of my invention is to secure a higher insulation, arelatively lower inductive capacity, and greater durability in insulatedelectrical conductors or cables.

Insulated conductors as usually constructed consist of a core of copperor other good conductor having wrapped, braided, or twisted thereon acoating of fibrous material, as silk or cotton, which material, eitherbefore its application to the conductor or immediately atterward, issaturated with an insulating sub stance, such as paraffine, tar, orresin. The degree of perfection to which this form of insulation attainsis, as I have found by experiment, in a great measure due to theexclusion of moisture from the fibrous and other insulating materialused. Heat alone fails to completely remove moisture from the cellularstructure of cotton, for instance, and the same is true of many otherfibrous materials, and also of the resins, gums, &c., used forinsulating conductors.

My invention consists in a process of insulating electrical conductorswhereby all moisture is removed from the insulating material, and forthis purpose I provide an airtight tank and means for exhausting the airtherefrom, as an air-pump operated by a steam-engine. I also provideone, two, or more tanks for the reception of the insulating materialwith which the fibrous coating is to be saturated, the number dependingon the number of substances which are to be used in succession, Allthese tanks are connected with the air-tight tank first mentioned bypipes having cocks or valves controlling the passage therethrough. Allthe tanks are provided with steam-jackets, whereby the temperature oftheir contents may be raised to any desired point. If three insulatingsubstances areto be v of insulating material.

successively applied, as is my custom, I place in each of three tanks,respectively,one species I then open the pipe connecting the first tankwith the airtight tank, and by creating a vacuum in said. tank draw inthe insulating substance from the first tank. I continue to exhaust fromthis tank till the gage indicates as nearly a perfect vacuum as isattainable, when,.the air and moisture being removed from the insulatingsubstance, I change the arrangement of valves and force the air into theair-tight tank.

This forces the insulating material back into the tank from which it wasdrawn. Of course suflicient heat must be maintained in the steamjacketsto keep the substance under treatment in a fluid state. The same processis then ap plied to substances in the second, third, and remainingtanks. The cable, composed of a series of conductors wrapped or braidedwith cotton or other fibrous material upon a light skeleton reel, is nowplaced in the air-tight tank and a high vacuum produced therein, whilethe temperature is considerably increased. This causes expansion in thecellular structure of the fibrous covering, which finally bursts anddischarges the contents of the cells. This, in the form of water, is nowdrawn off. The pipe-connection with thefirst tank containing aninsulating substance is opened, a vacuum produced in the cable-tank, andthe cable becomes submerged in the insulating material. Air-pressure isnow applied until the fibrous coating of the conductors is thoroughlysaturated or impregnated. The remaining material is driven back into thefirst tank and the operation last described pursued with the remainingsubstances in the second, third, and additional tanks. The cable is thenready to receive its armor of lead pipe orother appropriate protection.

The accompanying sheet of drawings illus' trates the arrangement ofmeans for practicing my process of insulation.

T is a tank having a cover, 25, which must be bolted or otherwisesecurely fastened down to form an air-tightjoint. Tank T is surroundedwith a steam-jacket, J. Air-pump P, operatcd by a steanrengine, and thecondenser C are connected to tank T bya pipe having cocks or valves 0 c"0, which are arranged for p roducing either a vacuum or pressure in thetank.

G G G are vacuum, pressure, and steam gages, respectively.

T T T are three tanks of substantially the same capacity as tank T. Iprefer to use for insulating substances two or three materials varyingin viscosity, and to apply the most liquid substance first, followingits application by that of a substance somewhat more viscous, and thisby other substances of relatively greater viscosity. To this end I placespirits of turpentine, pine-tar oil, and heavy pine-tar in the threetanks,respectively. Steam-jackets J may be placed upon the under side ofthese tanks. The tops are preferably open. Pipes connecting the steam-jackets and steamboiler are shown.

The tanks T T T being supplied with the insulating substances, asstated, the first tank, T, is opened into tank T through theconnecting-pipe, and a vacuum is formed in T, which draws the spirits ofturpentine into tank T. The inlet to T is then closed, and when the gageindicates as complete a vacuum as it is practicable to obtain theconnection with tank T is again opened, air-pressure is applied to tankT, and the turpentine is driven back into T, sufficient heat beingapplied to keep the turpentine in a semi-fluid state. The same operationis now gone through with respecting the contents of tanks T T. Tank T isnow uncovered, and the cable, composed of a series of conductors wound,braided, or twisted with some fibrous material, as cotton, upon a lightskeleton reel, is placed in tank T and the cover t placed in position.Steam is then caused to heat tank T to from 225 to 300 Fahrenheit, andwhile so heated a vacuum is produced in T, so that the moisture, vapors,and gases are entirely removed from the fibrous coating of the cable andthe minute pores swell up, burst, and discharge their contents, asappears upon microscopic examination. After the moisture, vapor, andgases have been so completely re moved from the fibrous coating that avacuum can be maintained in T, tank T is connected with T and theturpentine drawn into tank T, submerging the cable. The outlet of T isnow closed and air-pressure is applied of, say, four atmospheres, whichcauses the turpentine to impregnate the fibrous material, filling theminutest pores and interstices. The passage between T and T is againopened and the free turpentine is forced back into tank T. Thisoperation is applied to the insulating substances in the remainingtanks, which mnstbe properly heated, after which the tank T is openedand the cable removed.

The cable is now ready to receive its lead pipe or otherprotecting-armor. I prefer to use lead pipe and to braid, weave, or windover this a cover of cotton, hemp, or other fibrous material impregnatedaccording to my process with some substance to prevent decay.

I do not confine myself to the insulating materials above described, norto the use of any number of substances, and my process of treatingfibrous substances is equally applicable to the treatment of materialfor ropes, eordage, sail-cloth, &c.

I do not herein claim the means shown and described for practicing mymethod of insulation, nor do I claim the product 01' such 1nanufacture,as this forms the subject-matter of other applications.

\Vhat I claim is-- The process of insulating an electrical conductorherein described, which consists in covering the conductor with afibrous insulating material, subjecting it to the combined action ofheat and an air-pump operated to produce a vacuum until the combinedaction thereof bursts the cellular structure of the fibrous insulatingmaterial and dispels the moisture, and then applying insulating substance under pressure.

In testimony whereof I have signed my name to this specification,in thepresence of two subscribing witnesses, this 11th day of March, 1885.

JOHN T. JAQUES.

XVitnesses:

H. H. EUsTIs, GEO. K. LITTLEFIELD.

